Colognes And Headaches: What's The Real Connection?

It is not uncommon for people to experience headaches from fragrances. While some scents may be pleasant, they can also cause physical reactions such as headaches and nausea. Fragrances are made up of dozens of compounds or synthetic volatile chemicals that create an odour. These compounds can cross the blood-brain barrier and interact directly with receptors in the central nervous system. This can cause immediate changes in body functions, including blood pressure, brain activity, and pulse rate.

In addition, a person may be allergic to a chemical element in the fragrance, or they may have a fragrance sensitivity, which affects 1-4% of the general population. Fragrance sensitivity can cause various health effects, including neurological, skin, mucosal, gastrointestinal, and cardiovascular problems.

To prevent scent-related headaches, it is recommended to avoid strong scents, choose unscented products, and use scented products in well-ventilated areas.

Fragrance sensitivity

For individuals with fragrance sensitivity, exposure to fragranced products like perfume, air fresheners, and personal care items can trigger a range of symptoms. One of the most commonly reported issues is headaches, which can be intense and long-lasting. The exact mechanism by which fragrances trigger headaches is not fully understood, but several theories have been proposed. One theory suggests that fragrance compounds can cross the blood-brain barrier and interact with receptors in the central nervous system, leading to changes in body functions such as blood pressure, brain activity, and pulse rate.

Another hypothesis focuses on the role of the trigeminal pathway, a nerve pathway that transmits sensory signals from the head to the brain. Certain odours are believed to stimulate this pathway, causing inflammation as the body detects a threat and activates the immune system. This response can lead to vasodilation (widening of blood vessels) and headache pain. Additionally, some fragrances may contain chemical irritants that act as olfactory irritants, negatively affecting the trigeminovascular system, which is closely linked to headaches.

While the specific causes of fragrance-induced headaches are still being investigated, it is clear that fragrance sensitivity is a significant issue for a substantial number of people. These individuals often find relief by avoiding fragranced products, opting for unscented or natural alternatives, and seeking well-ventilated spaces.

Allergic reactions

Fragrances and perfumes are made up of dozens of compounds or synthetic volatile chemicals that create an odour. These chemicals can sometimes irritate our sinuses, causing allergy-like symptoms such as watering eyes, runny noses, and headaches.

The National Eczema Association suggests that fragrance sensitivity, which refers to sensitivity or allergic reactions to certain fragrances or perfumes, is present in 1–4% of the general population. However, an international 2019 study noted about one-third of adults across the United States, Australia, the United Kingdom, and Sweden report fragrance sensitivity.

Individuals with fragrance sensitivity reported various health effects upon exposure to fragranced products, including neurological and respiratory problems, skin problems, cognitive problems, gastrointestinal symptoms, cardiovascular problems, and musculoskeletal issues.

The chemicals that activate the smell signals in our brain (called odorants) can irritate the sinuses, and common odorants that cause irritation include smoke, perfume, and chlorine. When the body detects these irritants, it needs to produce more and more mucus to clear the trapped particles, resulting in allergy-like symptoms. This, in turn, causes our immune system to kick in, leading to vasodilation, inflammation, and, for some, headaches.

Some odours may also act directly on the trigeminal or trigeminovascular nerve pathway, which transmits sensory signals from our head to our brain for processing. When this pathway is stimulated, it causes inflammation because it detects a threat that only the immune system can address. This can also lead to headaches.

While there is still no solid evidence linking fragrance to headaches, some researchers believe that certain fragrances can cause blood vessels in the brain to pulsate, resulting in a headache or migraine. Others believe that odours can stimulate parts of the brain and nervous system responsible for head pain.

Blood vessel dilation

Vasodilation is the medical term for the widening of blood vessels, which allows more blood to flow through them and lowers blood pressure. This process happens naturally in the body without us realizing it. It is caused by the relaxation of smooth muscle cells within the vessel walls, particularly in the large veins, large arteries, and smaller arterioles.

Vasodilation occurs when the muscles in the blood vessel walls relax. This relaxation relies on removing the stimulus for contraction, which depends on intracellular calcium ion concentrations and is tightly linked with phosphorylation of the light chain of the contractile protein myosin. Vasodilation can be caused by:

• The removal of the stimulus for the contraction of smooth muscle cells, which depends on intracellular calcium ion concentrations.
• Dephosphorylation of the light chain of the contractile protein myosin.
• The release of certain natural chemicals such as carbon dioxide, nitric oxide, and the hormone prostaglandin.
• Alcohol consumption, which causes immediate vasodilation followed by an increase in blood pressure.
• Exercise, which requires more oxygen and nutrients to be delivered to the body's cells, particularly the muscle cells.
• Infection, which increases blood flow to the affected area to help the body fight the infection and repair any damage.
• Allergic reaction, which can lead to anaphylaxis, a severe and potentially life-threatening condition.

If vasodilation has caused a large drop in blood pressure, it can be treated with fluid resuscitation (giving IV fluids) and blood pressure-increasing medications such as vasoconstrictors and vasopressors.

Yes, depending on the cause, timing, and strength of the effect, vasodilation can have negative consequences. In extreme cases, it can even be life-threatening. For example, during anaphylaxis, a severe allergic reaction, the body goes into shock, and blood pressure drops dangerously.

Symptoms of Shock

• Altered mental state, including anxiety, agitation, or confusion.
• Blue coloration of lips and fingertips.
• Feeling dizzy, lightheaded, or fainting.
• Skin that is cool, clammy, or pale.
• Shallow or rapid breathing.

Fragrances and Vasodilation

Fragrances and perfumes are made up of dozens of compounds or synthetic volatile chemicals that create an odour. These chemicals can sometimes irritate our sinuses, and smoke, perfume, and chlorine are common odorants that can cause such irritation. This irritation can lead to vasodilation and inflammation, resulting in a headache.

Additionally, fragrance compounds can cross the blood-brain barrier and interact directly with receptors in the central nervous system, producing immediate changes in body functions such as blood pressure, brain activity, and pulse rate.

Managing Fragrance-Induced Headaches

If you tend to get headaches from fragrances and perfumes, it is best to avoid them as much as possible. When triggers cannot be avoided, fresh air and painkillers may help manage any headaches that occur.

Trigeminal pathway stimulation

The trigeminal nerve is a cranial nerve that carries sensory signals from the nose and mouth to the brain. It is believed that certain scents can trigger the trigeminal nerve, which may be the cause of cologne-induced headaches. This is known as the trigeminal pathway stimulation.

The trigeminal nerve is responsible for transmitting sensory information to the brain, including touch, pain, and temperature. When the trigeminal nerve is stimulated by certain scents, it can cause inflammation as the immune system detects a threat. This inflammation can lead to headaches.

Some common odorants that are known to irritate the sinuses and activate the trigeminal pathway include smoke, perfume, and chlorine. These odorants can cause a fight or flight stress response in the body, leading to physical changes such as increased blood flow to the brain and widening of the blood vessels in the head and neck. This can result in a headache.

In addition to causing inflammation, scent molecules can also cross the blood-brain barrier and interact directly with receptors in the central nervous system. This can lead to immediate changes in body functions, including blood pressure, brain activity, and pulse rate.

Furthermore, it is suggested that scents may trigger the release of inflammatory substances in the brain, causing pain. This can activate the trigeminovascular system and dural pain receptors, leading to a state of reactivity that lowers the threshold for pain. This can result in allodynia, which is the experience of pain from a stimulus that typically does not cause pain.

While the exact mechanism of how scents trigger headaches is not fully understood, it is believed that the trigeminal pathway stimulation plays a crucial role. This stimulation can cause inflammation, interact with receptors in the central nervous system, and trigger the release of inflammatory substances, all of which can contribute to headache pain.

Osmophobia

The term osmophobia comes from the Greek word "osmē," meaning "smell, odour," and "phobos," meaning "fear." Olfactophobia comes from the Latin "olfacto," meaning "to smell at."

While osmophobia is not a definitive diagnostic criterion for migraines, it is a very common symptom, with 95% of migraine patients reporting it and 37.9% of patients reporting it in at least 20% of their headache episodes. It is also associated with symptoms of central sensitization, such as allodynia, and factors facilitating it, such as psychopathological traits.

People with osmophobia may experience longer migraine durations, higher migraine-related impairment, and higher levels of anxiety and depression. They may also be more prone to experiencing olfactory hallucinations, or smelling things that are not present, during a migraine attack.

In addition to migraines, osmophobia may also be present in individuals experiencing substance withdrawal, particularly opioid withdrawal syndrome, where it is usually associated with nausea and/or vomiting.

Perfumes and colognes are among the most common triggering scents for osmophobia, along with cigarette smoke, car exhaust, and cleaning products.

Frequently asked questions